From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A7B814290C; Sun, 1 Sep 2024 16:24:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725207885; cv=none; b=kZb7V+NMRqR9tdw6j6Ew88GfEj7OQ7W44Ur9t4NAsXp2cxdmU0YuEOy+KT9V/btlqShV0q8cS8HLyP96Rio9spYr3nXjaC3UPTuhGpEQC8GLMcRZKGTlD9GrliY0w/bFDuOorbtgCMdNL+HjUrL/3g4+WA5IMMgl6Ncdh8p+C/Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725207885; c=relaxed/simple; bh=hx3HbfcNhzTm4gkSlp3stk1+CvdmsZEKbZecv7mBnZw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ghHQUc9g4pDgbOBVbuakZ98Pi0wRfSkx7V9u779zgdglvT9RDNjcsrV2k7BULyxp+DWZ4AEvzFXtAAsBtqUpPZqji/mReeJv+S0c9iGnRFOiupSGfAnTbGfY/PH2pd4ONQE+iqg4kql/j6pvdGSq8CUxy3ifI37DCrLTQtSXpu8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xKUN1fxj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xKUN1fxj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D01EFC4CEC3; Sun, 1 Sep 2024 16:24:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725207885; bh=hx3HbfcNhzTm4gkSlp3stk1+CvdmsZEKbZecv7mBnZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xKUN1fxjDt7cDdKeO02fK+lpowBbOv0ebj33I+KcbBAd0MzzrUQhzggTm3qa5JD3t p2iQgXtbqgPTq/Fe8/3+cCn7V4WykrZ2HjnJLBf1w7rUKGJwVhnht51ejIvAM2IXj0 IysXWlvvVivYx9vHpT0ZBwZIKmu1IxXXBxuMnhWQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Mina Almasry , Willem de Bruijn , Joe Damato , Jakub Kicinski , Sasha Levin Subject: [PATCH 4.19 89/98] net: busy-poll: use ktime_get_ns() instead of local_clock() Date: Sun, 1 Sep 2024 18:16:59 +0200 Message-ID: <20240901160807.053982274@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240901160803.673617007@linuxfoundation.org> References: <20240901160803.673617007@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 0870b0d8b393dde53106678a1e2cec9dfa52f9b7 ] Typically, busy-polling durations are below 100 usec. When/if the busy-poller thread migrates to another cpu, local_clock() can be off by +/-2msec or more for small values of HZ, depending on the platform. Use ktimer_get_ns() to ensure deterministic behavior, which is the whole point of busy-polling. Fixes: 060212928670 ("net: add low latency socket poll") Fixes: 9a3c71aa8024 ("net: convert low latency sockets to sched_clock()") Fixes: 37089834528b ("sched, net: Fixup busy_loop_us_clock()") Signed-off-by: Eric Dumazet Cc: Mina Almasry Cc: Willem de Bruijn Reviewed-by: Joe Damato Link: https://patch.msgid.link/20240827114916.223377-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/busy_poll.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h index 8f42f6f3af86f..c45253ee08c9f 100644 --- a/include/net/busy_poll.h +++ b/include/net/busy_poll.h @@ -73,7 +73,7 @@ static inline bool sk_can_busy_loop(struct sock *sk) static inline unsigned long busy_loop_current_time(void) { #ifdef CONFIG_NET_RX_BUSY_POLL - return (unsigned long)(local_clock() >> 10); + return (unsigned long)(ktime_get_ns() >> 10); #else return 0; #endif -- 2.43.0